OK...the herd is now fed. Before I bounce off to feed the human ones, let me give you at least this much to start, Krs. There's a marvelous book out there I highly recommend.
Fighting Malevolent Spirits: A Demonologist's Darkest Encounters Paperback – March 8, 2014
by
Samantha E. Harris
You can find that on Amazon. It covers angry spirits to demons, and everything in between. The best part is Samantha gives step by step instructions on how to deal with this. She uses the same methods I've used for over 40 years, and I know they work. She has prayers of protection as well, including the use of St. Michael the Archangel's prayer, which I would use daily in your home. I would also recommend the use of St. Benedict medals for protection in the apt. I'm Wiccan, but my best friend is a nun, and I have worked with the St. Ben medals for years with good success. I would also recommend wearing one at night to guard against the nightmares.
I would also recommend you listen to Bob Bain's interview's with Samantha herself. You can find those at Mysterious Matters with Bob Bain on youtube.
Since you don't have experience in cleansing, I have recommended the book so you can have the instructions IN HAND and look up things as you go. All the materials you need can be found online.
The thing here is, Krs, you either have to do something about this or it may just get worse. OR it will continue as it is. I know things could get worse, but there are pros out there to help you if you still feel afraid to try it on your own. Your faith has to be firm that YOU HAVE THE POWER OF THE DIVINE WITHIN YOU to order this thing out. You can't waiver, and you need to believe.
If you feel you just want to negotiate with it, simply sit down and talk to it out loud. Set firm boundaries. Claim the space as yours. Let it know your guidelines for co-existing. If things get worse fast, you'll know it's not willing to do so and you will have to take measures.
I'll be back later so any questions just let me know.